3 - You gonna create a very simple smoke over each exhaust pipe.
Click .
Draw an ellipse as shown, with a radial gradient color.
Name it fumee

Creating Effects

In Timeline, set a Transform effect for fumee
over 15 frames.

Ellipse is 45 height.
0,0 being the center, we start at its bottom with a Y-scale equal to 0 and X-scale 10%.
Right after place Fade Out effect over 5 frames.
You have therefore used 20 frames for the whole.

Copy object

1 - Copy and paste the previous object to the mentioned position :

2 - Select the 2 objects then menu Modify / Grouping / Group as Sprite.
Name it Effet. You'd yield

Script

In Outline, select Scene_1. Enter script

onLoad { Effet.stop(); }

In Outline, select the image, then enter the following script

When mouse is over image, a sound is played and sprite plays.
When mouse goes out, all is stopped.
Warning :
If another object owns an Over event, the previous effect 'll stop as soon as the mouse 'll be over that new object.
In fact, the mouse event is captured by the object.